The Congressional watchdog organization Citizens for Responsibility and Ethics in Washington (CREW) will file an official complaint against Sen. David Vitter (R-LA) tomorrow, urging Senate ethics investigators to probe several allegations of misconduct, TPM has learned.

All of the allegations relate to Vitter’s professional relationship with Brent Furer, a former top aide who was arrested in January 2008 for assaulting his then girlfriend with a knife, but remained on Vitter’s staff and working on women’s issues until June of this year when he resigned.

CREW contends that Vitter misused official funds in two ways.“Mr. Vitter was paying Mr. Furer for several months when Mr. Furer was not in the office because of the assault,” CREW’s Executive Director Melanie Sloan tells TPM.

That allegation is based on official statements and records from Vitter’s office, according to the complaint, obtained by TPM. “After the January 2008 incident he was told to leave the office pending the court’s determination of what happened,” Vitter’s spokesman Joel DiGrado said in a statement after Furer’s resignation. “In April, after the court issued its penalty…he was allowed to return to the office.”

CREW alleges that between January and April 2008, Furer only went without pay for five days.

Separately, according to Sloan, “Mr. Furer was going to Louisiana to make court dates and Senate resources were used to pay for his trips.”

The complaint cites two trips Furer took to Louisiana from Washington, both of which were paid for, according to official expense records, with Senate funds. The official travel costs included air fare, per diem and incidental expenses totaling over $1,000.00.

“It’s clearly an abuse of official resources,” Sloan said.

CREW also claims that Vitter may have violated Senate conduct rules by publicly claiming that Furer was not assigned to work on women’s issues after the January 2008 incident when records and public accounts indicate that he was.

Finally, the complaint urges the Ethics Committee to investigate whether Vitter helped Furer secure or pay his defense attorney Thomas Kelly, of the Venable law firm. Kelly’s billing rate at Venable, according to the complaint, is $530 per hour. At the time, Furer was earning $47,999 a year.

In a June interview with TPM Kelly claimed not to recall whether Vitter helped Furer retain his services, but insisted the legal costs were minimal and that he does not know Vitter or anybody on his staff.